103 patients with retinal-artery occlusion causing permanent visual-field defect were examined clinically and angiographically to assess the extent of cardiovascular disease. The 68 patients with branch-artery occlusion had a higher prevalence of previous transient episodes, ischaemic and valvular heart-disease, and more often had an operable lesion in the carotid artery than had the 35 patients with central-artery occlusion who were more often hypertensive, had fewer warning attacks, a greater prevalence of complete carotid occlusion, and fewer operable carotid lesions. The two types of retinal vascular occlusion show aetiological differences; branch occlusion is more often embolic and should be fully investigated for carotid and cardiac disease. These measures are less often of practical importance in patients with central-artery occlusion.